When I try to connect to the server by FTP protocol, it shown this error. I think there must be some problem with listing files, so I want to change the list command. However, I found the option is disabled. Does anybody know how to solve this?

You have probably selected SFTP protocol, so the option is disabled. But WinSCP falled back to old SCP protocol, when connecting, because it was not able to setup SFTP. Select SCP protocol explicitly._________________Martin Prikryl